Identification of Sequences Necessary for the Regulation and Function of p33 in Carrot

植物细胞壁中的Extensin mRNA和蛋白在损伤、乙烯、病原体感染和真菌和植物细胞壁激发子暴露的反应中增加，表明该细胞壁蛋白具有保护功能。该项目研究胡萝卜储存根和大豆中的另一种细胞壁蛋白p33，这种蛋白在受伤组织中也会增加，并在正常植物发育中发挥作用。最近发现的一些富含脯氨酸/羟脯氨酸的蛋白基因与胡萝卜p33序列具有同源性，这表明p33可能是一类新的细胞壁结构蛋白。启动子缺失分析用于鉴定受伤胡萝卜根中负责合成p33的DNA序列。这些研究将允许在受伤组织中调节p33表达的顺式作用区域，并允许确定这些相同的序列是否用于调节正常植物发育过程中p33的表达。胡萝卜p33序列特定区域的缺失分析将用于确定p33蛋白内可能的“结构域”，这是其功能和与其他细胞壁成分相互作用所必需的。这些结构域缺失研究将为鉴定高等植物细胞壁结构蛋白功能所需的序列提供新的途径。高等植物细胞壁是一种动态结构，其组成和结构随细胞年龄、组织类型和环境刺激而发生变化。细胞壁结构蛋白成分的大部分分析都涉及延伸蛋白，一种富含羟基脯氨酸的糖蛋白，以及编码它的基因。本研究的重点是一个新发现的细胞壁蛋白，它在植物的正常生长中起作用

Extensin mRNA and protein in plant cell walls have been shown to increase in response to wounding, ethylene, pathogen infection and exposure to fungal and plant cell wall elicitors, suggesting a protective function for this cell wall protein. This project studies another cell wall protein in carrot storage roots and soybean, called p33, that also increases in wounded tissue and also plays a role in normal plant development. The recent identification of a number of proline/hydroxyproline-rich protein genes which share sequence homology with the carrot p33 sequence suggests that p33 may represent a new class of structural cell wall proteins. Promoter deletion analysis is used to identify DNA sequences which are responsible for the synthesis of p33 in wounded carrot roots. These studies will allow the cis-acting regions which modulate p33 expression in wounded tissue and allow determination of whether these same sequences are used to regulate the expression of p33 during normal plant development. Deletion analysis of specific regions of the carrot p33 sequence will be used to identify possible "domains" within the p33 protein necessary for its function and interaction with other cell wall components. These domain deletion studies will represent a new approach to identifying sequences which may be necessary for the function of structural cell wall proteins in higher plants.%%% The cell walls of higher plants are dynamic structures which undergo changes in composition and structure in relation to cell age, tissue type and environmental stimuli. Much of the analysis of the structural protein component of the cell wall has dealt with extensin, a hydroxyproline-rich glycoprotein, and the genes which encode it. This study centers on a newly discovered cell wall protein which plays a role in normal plant growth.***//